The keyword "DISTINCT" is utilized in PROC SQL to ensure that only unique results are returned from a query. When you include "DISTINCT" in your SQL statement, it filters out duplicate rows from the result set, enabling you to obtain a consolidated view of the data without repetitions. This is particularly useful when you want to see different values in a specific column or combination of columns, enhancing data analysis by making it easier to identify diverse entries.
For instance, when querying a table for a list of customers, and many customers have repeated entries due to multiple transactions, using "DISTINCT" would allow you to retrieve a list where each customer's name appears only once, thus making the output more meaningful.
The other choices do not reflect the correct terminology used in PROC SQL for this operation, which further emphasizes the necessity of understanding the syntax and structure of SQL when working with data retrieval in SAS.